Originally Posted by Polwart
Reversing definitely the hardest bit
A trick I learned was to grab the steering wheel at the bottom; then to move the trailer to one side or the other, push your hands in that direction.
Weird thing about backing is that it's not a constant turn: Once you get the trailer on a different axis than the tow vehicle, you can't go straight back without the angle getting bigger. To keep a constant turn, you have to "chase" the trailer around the curve.
Go slowly, and use many small corrections (rather than less often big corrections), and don't be afraid to abort, pull forward to straighten things out and start over.
While going straight forward, memorize the image of how the trailer looks in your side mirror; that will give you a reference for going straight backwards (which also means you can tell if the trailer is turning one way or the other.)
Once you get used to it, the only thing you have to worry about is backing the wrong way just after removing the trailer.